Metamorphic protein IscU alternates conformations in the course of its role as the scaffold protein for iron-sulfur cluster biosynthesis and delivery.

ABSTRACT: IscU from Escherichia coli, the scaffold protein for iron-sulfur cluster biosynthesis and delivery, populates a complex energy landscape. IscU exists as two slowly interconverting species: one (S) is largely structured with all four peptidyl-prolyl bonds trans; the other (D) is partly disordered but contains an ordered domain that stabilizes two cis peptidyl-prolyl peptide bonds. At pH 8.0, the S-state is maximally populated at 25 °C, but its population decreases at higher or lower temperatures or at lower pH. The D-state binds preferentially to the cysteine desulfurase (IscS), which generates and transfers sulfur to IscU cysteine residues to form persulfides. The S-state is stabilized by Fe-S cluster binding and interacts preferentially with the DnaJ-type co-chaperone (HscB), which target

SUBMITTER: Markley JL 

PROVIDER: S-EPMC3960074 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature